Antibodies, lymphocytes and diversity

Question 1

Describe the receptor on the surface of T-cells

Answer 1

Heterodimer with alpha and beta chains + one binding site unique to the cell.

Question 2

Describe the receptor on the surface of B-cells

Answer 2

Made up of 2 identical heavy and 2 identical light chains with 2 antigen binding sites per cell.

Question 3

What are the segments that make up the variable region of the heavy chain binding site on the surface of a lymphocyte?

Answer 3

Variable (V), diversity (D) and joining (J) segments.

Question 4

Which chromosome is the gene for the antibody heavy chain protein?

Answer 4

chromosome 14

Question 5

How many different options are there for each segment of the heavy chain, variable region of the receptor on the surface of a lymphocyte

Answer 5

48 for V, 27 for D and 6 for J.

Question 6

What are the segments that make up the variable region of the light chain binding site on the surface of a lymphocyte?

Answer 6

Variable (V), and joining (J)

Question 7

What bonds hold together an immunoglobulin?

Answer 7

Disulfide bonds

Question 8

What are the classes of immunoglobulins?

Answer 8

IgM, IgG, IgA, IgE, IgD

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Question 9

What is the Fc region of an immunoglobulin?

Answer 9

Paired constant region segments. Macrophages have Fc receptors so they can wear antibodies like hats.

Question 10

What are the subclasses of IgG immunoglobulins?

Answer 10

IgG 1,2,3,4

Question 11

What are the subclasses of IgA immunoglobulins?

Answer 11

IgA 1,2

Question 12

What is the main antibody in serum?

Answer 12

IgG

Question 13

What are the IgG subclasses present in serum in decreasing order of abundance?

Answer 13

IgG1, IgG2, IgG3, IgG4

Question 14

Where is dimeric IgA found?

Answer 14

Mucosal surfaces; joins to secretory component on basolateral membrane on cells.

Question 15

What joins two IgA monomers to form an IgA dimer?

Answer 15

A J chain.

Question 16

What is the first antibody made in an immune response?

Answer 16

Pentameric IgM - has 10 binding sites so has a high avidity, good for agglutination.

Question 17

What effect does IgE have when it binds to cells?

Answer 17

Histamine is released.

Question 18

Where does antibody specificity/affinity maturation occur?

Answer 18

In the germinal area of the lymph node.

Question 19

What is affinity maturation of antibodies?

Answer 19

The antigen of the pathogen is stored in the germinal centre of the lymph node. Then antibodies are tested against it, then new ones are produced and tested so there is a selection allowing for antibodies to be more specific to the antigen produced.

Question 20

What type of cells leave the germinal centre of the lymph node following the affinity maturation?

Answer 20

Memory cells and plasma cells

Question 21

What are monoclonal antibodies?

Answer 21

Identical clones of an antibody in which variable regions are produced in mice and constant regions sourced from humans (to prevent inappropriate immune response)

Question 22

What ending is given to the names of drugs which are chimeric antibodies?

Answer 22

-ximab

Question 23

What ending is given to the names of drugs which are humanised antibodies?

Answer 23

-xumab

Question 24

What is haemolytic disease of the newborn?

Answer 24

at least second Rhesus positive baby born to a rhesus negative mother